While that leads to many questions, one at the forefront is if Yahoo sells off Yahoo Mail and its news and sports sites -- and especially if it sells its search business -- what does that leave? Will there be more to the business than a skeleton picked clean of most anything of value?

If those sales do happen, the Yahoo that has been known as an Internet and search company for the past 20 years would cease to exist.

It may not take long to find out what's brewing at Yahoo. The board is holding a meeting today, potentially talking about Mayer's continued work there and about dumping some of its core business.

The board also is expected to take on Yahoo's potentially spinning off its 15% share of Alibaba, the Chinese e-commerce giant, into a new public company in an attempt to avoid an enormous tax bill. The possible spinoff has been met with both support and criticism.

"I'm expecting big news, either a CEO change, a major reorganization, a major strategic shift, or some kind of sale," said Moorhead. "Investors are driving the narrative here. They're unhappy, want action, and want it now. The same pressures that got Mayer the job could unseat her."

When Mayer left her long-held executive position at Google to become Yahoo's CEO in the summer of 2012, there were high expectations of what she might do.

At the time, Mayer was Yahoo's third CEO in less than a year and she was taking over a very troubled company.

After one CEO was let go and another stepped down after it came to light that his listed academic credentials weren't legitimate, Yahoo had been eclipsed by Internet giants Google and Facebook, and had also become mired in financial trouble.

On the positive side, Mayer was behind more than a dozen acquisitions, including the purchase of Tumblr and Summly. She also pushed the company to focus on mobile devices but then failed to find a significant way to monetize it.

​Over the last few years, Yahoo also has launched new products, including new mobile mail video apps, but none of them were blockbusters. While Mayer has picked up a talent from around Silicon Valley, she's also had top executives jump ship.

Mayer also caused a stir when she called in the company's telecommuters, saying the company needed employees to work more creatively and efficiently and they could do that better in the office than at home.

Most significantly, Yahoo still hasn't stabilized its finances. The company's net revenue has dropped from $5.4 billion in 2008 to an expected maximum of $4 billion this year.

With the great hype and excitement around Mayer's hiring and then without the anticipated grand turnaround, investors and board members could be getting antsy. And that means they want change.

How significant that change will be is what people are waiting to see now.

"Yahoo is kind of a mess," said Rob Enderle, an analyst with the Enderle Group. "The proposed plan is to effectively sell off a lot of things and build a new and different company from scratch. It is an interesting idea because it literally would make them into a universal startup. I have my doubts Mayer will survive, regardless."

Jeff Kagan, an independent industry analyst, said Yahoo hasn't seen the epic turnaround but he doesn't necessarily blame Mayer.

"This was a gargantuan task, especially in the shadow of what Google had done in transforming the industry," he said. "I believe Yahoo is right where it was before Mayer came aboard. If they can't fix it, break it up and sell the parts.

"Unfortunately, I think Yahoo has already bit the dust but no one has told them yet," Kagan added. "What the future holds for Yahoo has been the question for the last decade and it's still the question."